Arrangement of a Catalytic Converter in an Exhaust System

ABSTRACT

An arrangement of a catalytic converter in an exhaust system of an internal combustion engine which can be operated with fuel containing manganese is provided, wherein the catalytic converter is arranged in the exhaust tract in an exhaust gas flow path from the internal combustion engine. A sacrificial disk, which is permeable to exhaust gas, is arranged in the exhaust tract upstream of the catalytic converter in the flow direction of the exhaust gas. When the exhaust gas back pressure becomes too high for normal internal combustion engine operation owing to manganese deposits, the relatively inexpensive sacrificial disk can be replaced other than exchanging and/or cleaning the relatively expensive catalytic converter.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of PCT International Application No. PCT/EP2011/002743, filed Jun. 3, 2011, which claims priority under 35 U.S.C. §119 from German Patent Application No. DE 10 2010 025 804.0, filed Jul. 1, 2010, the entire disclosures of which are herein expressly incorporated by reference.

BACKGROUND AND SUMMARY OF THE INVENTION

The invention relates to an arrangement of a catalytic converter in an exhaust gas system of an internal combustion engine, which can be operated with fuel that contains manganese, wherein the catalytic converter is arranged in the exhaust gas system in a flow path of an exhaust gas of the internal combustion engine through the exhaust gas system.

A plethora of national and international standards specify the minimum requirement for Otto fuels. For example, EN 228 (European standard) describes unleaded gasoline (Euro super) imported into Europe. In addition and beyond the European standard, unleaded regular and super plus fuels are also described in the German national edition DIN EN 228. In the USA, Otto fuels are specified in ASTM D439 (American Society for Testing and Materials). Otto fuels are composed of hydrocarbons, which may contain additions of oxygenated, organic components as well as additives for enhancing the properties of the fuels. Furthermore, a distinction is made between regular fuel and super fuel. Super fuel has a higher anti-knock rating for running high compression internal combustion engines. In addition, various volatility characteristics apply to summer and winter as well as to different regions.

As described above, the standards for Otto fuels differ widely from country to country. The drawback with such diverse standards is that Otto fuels may also contain different additives or impurities in different countries. In this context, the term “impurities” is understood to mean, for example, manganese, aluminum, phosphorus, silicon, zirconium, magnesium, zinc and calcium. These impurities are mentioned merely to give a few examples, because significantly more elements can be present in the Otto fuel.

These elements, in particular manganese, can become apparent in a negative way as deposits on the inflow face of a catalytic converter in the exhaust gas system of an internal combustion engine. In this respect it is interesting to observe that only the front face of the catalytic converter is affected by the deposits. Left to itself, this process will eventually result in up to more than 90% of the front face being clogged by the deposits, so that an exhaust gas back pressure builds up. This exhaust gas back pressure, in turn, no longer allows the internal combustion engine to run. That is, the internal combustion engine lacks power and torque. Usually, such dirty catalytic converters are replaced in the framework of a trip to the service center or are cleaned in a time consuming process; and both alternatives are very expensive and time consuming for the motor vehicle manufacturer or the customer.

Therefore, it is an object of the invention to overcome these problems and avoid the need for replacing such a dirty catalytic converter.

This and other objects are achieved by an arrangement of a catalytic converter in an exhaust gas system of an internal combustion engine, which can be operated with fuel that contains manganese, wherein the catalytic converter is arranged in the exhaust gas system in a flow path of an exhaust gas of the internal combustion engine through the exhaust gas system. A sacrificial disk, that is permeable to exhaust gas, is arranged in the exhaust gas system upstream of the catalytic converter in a direction of the exhaust gas.

Owing to the inventive arrangement of an inexpensive sacrificial disk upstream of the catalytic converter in the direction of flow of the exhaust gas, the manganese deposits form on the sacrificial disk and not on the front face of the catalytic converter. As a result, the expensive catalytic converter does not have to be replaced in the event that the exhaust gas back pressure becomes too high or in the course of a car service interval, rather only the inexpensive sacrificial disk needs to be replaced. Immediately after the sacrificial disk has been replaced, the catalytic converter will begin to show its normal catalytic converter startup, after the catalytic converter has reached the “light off” temperature, i.e. the temperature, at which the catalytic converter shows 50% of its total conversion properties. Even the conversion properties of the catalytic converter for noxious substances, such as hydrocarbons (HC), carbon monoxide (CO) and nitrogen oxides (No_(x)), remain practically unchanged.

In one embodiment, the sacrificial disk covers at least 70% of the flow cross-section of the exhaust gas system. This makes it possible to prevent the internal combustion engine from totally shutting down, because up to maximally 30% of the flow cross section can be provided for a “limp home” capability of the internal combustion engine.

In a preferred embodiment, the sacrificial disk has a thickness between 2 mm and 50 mm in the flow direction of the exhaust gas. This thickness of the sacrificial disk has proven in practical trials to be especially advantageous, because the manganese deposits form, in particular, in the first millimeters downstream of the front face of the catalytic converter or, more specifically, downstream of the sacrificial disk according to the invention.

In further preferred embodiments, the sacrificial disk is made of an interwoven fabric, a knitted fabric, a non-woven fabric, and/or a catalytic converter support body. The sacrificial disk may have a gas permeable cell size of 20% to 400% of the cell size of the catalytic converter.

In one aspect of the invention, the sacrificial disk has an anti-twist locking element and/or an axial securing element. Flow losses due to the sacrificial disk can be minimized because the spatial position of the sacrificial disk with respect to the catalytic converter can be positioned very precisely. Furthermore, it is possible to prevent in an advantageous way the sacrificial disk and the catalytic converter from being blocked on account of the sacrificial disk sliding away.

Preferably, the exhaust gas system has a closable opening, in order to allow for removal of the sacrificial disk. In that regard, a clamp, in particular a band clamp, may be provided for closing the opening. These embodiments make it possible to replace the sacrificial disk in an easy way. A closure that is especially preferred for use includes a clamp, in particular, a band clamp or a V band clamp or also a flange, etc.

In a preferred arrangement, an exhaust gas turbocharger is provided for the internal combustion engine. A turbine of the exhaust gas turbocharger is arranged in the exhaust gas track. The sacrificial disk may be arranged between the turbine and the catalytic converter. With this arrangement, the connection, which is present in any event, typically a V band clamp, between the exhaust gas turbocharger and the catalytic converter can be used for replacing the sacrificial disk.

Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a photo showing the front face of a dirty catalytic converter; and

FIG. 2 is a simplified schematic diagram illustrating an exhaust gas system according to an exemplary embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a photo of a front face of a catalytic converter 1, which is contaminated with deposits 2. This catalytic converter is arranged in a housing 3 of the catalytic converter. Chemical analyses have shown that these deposits 2 are composed, in particular, of manganese; and these deposits clog the front face of the catalytic converter 1, against which the exhaust gas of the internal combustion engine flows, in the exhaust gas system in the course of running the internal combustion engine, when the internal combustion engine is operated with fuel that contains manganese.

In order to reduce the increase in the exhaust gas back pressure that is generated by the clogging and that consequently results in a reduction in power and torque, a sacrificial disk that is permeable to exhaust gas is arranged in the exhaust gas system upstream of the catalytic converter in the direction of flow of the exhaust gas.

Referring to FIG. 2, for example, an exhaust tract 5 has arranged therein the catalytic converter 1. The exhaust gas flow through the exhaust tract 5 is represented by arrows 6. A sacrificial disk 4, which is permeable to the exhaust gas flow from the internal combustion engine (not shown) is arranged in the exhaust tract 5 upstream of the catalytic converter 1.

The term “sacrificial disk” is understood to mean any type of disk that is permeable to exhaust gas and is temperature stable and that is less expensive than a catalytic converter and, as a result, can be “sacrificed”, before a costly catalytic converter has to be replaced.

This sacrificial disk covers preferably at least 70% of the flow cross section of the exhaust gas system, as a result of which the deposits on the catalytic converter are prevented or at least minimized. Consequently a “limp home” capability of the internal combustion engine can be guaranteed owing to a possible flow gap.

Furthermore, the sacrificial disk has preferably a thickness between 2 mm and 50 mm in the flow direction 6 of the exhaust gas, because the manganese deposits form on the front face or in the first millimeters downstream of the front face of the catalytic converter or, more specifically, downstream of the sacrificial disk.

The sacrificial disk can be constructed of an interwoven fabric, a knitted fabric, a nonwoven fabric and/or a catalytic converter support body without a precious metal coating. The crucial feature is a mandatory exhaust gas permeability. For example, a metal wire may be used for the interwoven, knitted or nonwoven fabric. The catalytic converter support body can be, for example, metallic or ceramic.

The interwoven fabric, the knitted fabric, the nonwoven fabric and/or a catalytic converter support body of the sacrificial disk exhibit preferably a gas permeable cell size of 20% to 400% of the cell size of the catalytic converter.

In order to minimize flow losses for the exhaust gas, the sacrificial disk has, preferably, an anti-twist locking element and/or an axial securing element. With this embodiment, the flow losses caused by the sacrificial disk are minimized, because the spatial position of the sacrificial disk with respect to the catalytic converter can be positioned very precisely. In addition, a destruction of the catalytic converter due to the sacrificial disk sliding away because of the pulsating exhaust gas is prevented.

In order to be able to replace the sacrificial disk with ease, the exhaust gas system has preferably a closable opening 7. In this case a clamp 8, in particular, a band clamp or a V band clamp or also a flange, etc. is provided, in order to close the opening.

Since the catalytic converter may be arranged in close proximity to a turbine outlet in the case of an internal combustion engine with an exhaust gas turbocharger, both have more or less the same diameter so that the sacrificial disk can be easily replaced by detaching the band clamp between the catalytic converter and the turbine housing.

As a result, the catalytic converter does not have to be replaced, when the exhaust gas back pressure becomes too high for a normal operation mode of the internal combustion engine owing to the manganese deposits, but rather only the inexpensive sacrificial disk is replaced.

LIST OF REFERENCE NUMERALS

-   1 catalytic converter -   2 deposits -   3 housing of the catalytic converter -   4 sacrificial disk -   5 exhaust tract -   6 arrows showing gas flow -   7 closing opening -   8 clamp

The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof. 

What is claimed is:
 1. An exhaust gas system arrangement, for an internal combustion engine, comprising: a catalytic converter arranged in an exhaust gas flow path of an exhaust tract of the internal combustion engine, the internal combustion engine being operable with fuel containing manganese; a sacrificial disk, which is permeable to the exhaust gas of the internal combustion engine, arranged in the exhaust tract upstream of the catalytic converter.
 2. The arrangement according to claim 1, wherein the sacrificial disk is operatively configured to cover at least 70% of a flow cross-section of the exhaust tract.
 3. The arrangement according to claim 2, wherein the sacrificial disk has a thickness between 2 mm and 50 mm in a flow direction of the exhaust gas.
 4. The arrangement according to claim 1, wherein the sacrificial disk has a thickness between 2 mm and 50 mm in a flow direction of the exhaust gas.
 5. The arrangement according to claim 1, wherein the sacrificial disk is made of at least one of an interwoven fabric, a knitted fabric, a nonwoven fabric, and a catalytic converter support body.
 6. The arrangement according to claim 5, wherein the sacrificial disk has a gas permeable cell size of 20% to 400% of a cell size of the catalytic converter.
 7. The arrangement according to claim 1, wherein the sacrificial disk comprises at least one of an anti-twist locking element and an axial securing element.
 8. The arrangement according to claim 2, wherein the sacrificial disk comprises at least one of an anti-twist locking element and an axial securing element.
 9. The arrangement according to claim 3, wherein the sacrificial disk comprises at least one of an anti-twist locking element and an axial securing element.
 10. The arrangement according to claim 1, wherein the exhaust tract comprises a closable opening, the closable opening being operatively configured to allow for removal of the sacrificial disk from the flow path of the exhaust gas.
 11. The arrangement according to claim 2, wherein the exhaust tract comprises a closable opening, the closable opening being operatively configured to allow for removal of the sacrificial disk from the flow path of the exhaust gas.
 12. The arrangement according to claim 3, wherein the exhaust tract comprises a closable opening, the closable opening being operatively configured to allow for removal of the sacrificial disk from the flow path of the exhaust gas.
 13. The arrangement according to claim 10, further comprising a clamp operatively configured to close the closable opening.
 14. The arrangement according to claim 13, wherein the clamp is a band clamp.
 15. The arrangement according to claim 1, further comprising: an exhaust gas turbocharger having a turbine arranged in the flow path of the exhaust gas of the internal combustion engine; and wherein the sacrificial disk is arranged between the turbine and the catalytic converter.
 16. The arrangement according to claim 15, further comprising a band clamp operatively configured to couple a housing of the turbine and the catalytic converter, said band clamp being detachable to allow for replacement of the sacrificial disk. 